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Zou, Jammy

University of British Columbia

As the world’s population ages, the number of people affected by dementia and the overall burden of the disease continues to grow. Research dedicated to refining strategies to reduce the risk of cognitive decline and dementia are of vital importance to promote cognitive health. Exercise can play a neuroprotective role by mitigating the consequences of physical inactivity such as low muscle strength and cardiorespiratory fitness. However, limited studies have focused on examining the contribution of muscle strength and cardiorespiratory fitness for maintaining cognitive function in mid-to-late life. In this thesis, I conducted a secondary analysis using the Canadian Space Agency (CSA) Inactivity Study, a randomized controlled trial (RCT) of either: 1) 14 days 6° head-down tilt bed rest (HDBR); or 2) HDBR with daily resistance training (RT) and aerobic training (AT) to examine the independent and relative contribution of change in muscle strength and change in cardiorespiratory fitness on cognitive function in adults aged over 55 years. Results from multiple linear regressions showed that change in muscle strength, but not cardiorespiratory fitness was significantly associated with improved executive function following 14 days of HDBR. This finding prompted the inclusion of the Reshaping the Path of Vascular Cognitive Impairment (RVCI) trial, a RCT of 12-month, twice-weekly RT vs. active control in community-dwelling adults with vascular cognitive impairment to further examine the relationship between change muscle strength and cognitive function. Using data from RVCI, results from multiple linear regressions showed that muscle strength was positively associated with processing speed and working memory. The RVCI dataset addresses the limitations of the CSA study by providing a larger sample size, a non-HDBR sample, and a greater RT stimulus. This thesis provides preliminary evidence that maintaining muscle strength may be critical for preserving cognitive function in aging adults who experience bed rest or have cerebral small vessel disease. Importantly, this thesis prompts future research to examine: 1) the effect of exercise modality; and 2) the mediating factors between exercise and cognitive health. A better understanding will inform public health policies to help provide more precise exercise recommendations that focus on promoting healthy cognitive aging.

Text

2024-04-29

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/88075

Rehabilitation Sciences

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/